It’s not easy to see an egg cooking in the shell, but this guide will help you get it right almost every time.

It takes around 20 and 30 minutes to boil potatoes depending on their size.

Potatoes are cooked once they are soft enough for a knife to slice through with little resistance, though this varies. Some potato varieties are what is called ‘waxy’. This means they do not allow water to breakdown the starch structure when cooking. Your typical salad potato is waxy.

The other type of potato is called ‘floury’, which starts to break apart during the boiling process. So floury potatoes are good for roasting. The best roasted potatoes are done by partly boiling the potato pieces for 10 minutes then draining them and transferring to hot oil in an oven to finish cooking and crisping up. The floury outer surfaces of the potatoes make the roasted potatoes very crispy.

Start to test your potatoes with a knife about 10 minutes into the cooking toes how they are doing. When the knife is easily pushed into the potato, it is done!